1. Field of the Invention
The present invention relates to needles for a medicament delivery device, such as a pen injection device or a syringe, and more particularly, to a multiple needle changing apparatus for a medicament delivery device.
2. Description of the Related Art
Medicament delivery devices are used for self-injection of precisely measured doses of medication. Pen injection devices are widely used, for example, by diabetics to self-inject insulin. A typical medicament delivery pen includes a cartridge that contains a volume of liquid medication sufficient for several doses. Using a pen needle attached to the pen injection device, the dose is injected into a tissue area, such as the intramuscular tissue layer, the subcutaneous tissue layer, or the intradermal tissue layer.
The assembly and operation of a typical pen injection device is described in commonly-assigned U.S. Patent Application Publication No. 2006/0229562, published on Oct. 12, 2006, which is hereby incorporated by reference in its entirety.
Pen injection devices, such as an exemplary pen injector 50 shown in FIGS. 1 and 2, typically comprise a dose knob/button 24, an outer sleeve 13, and a cap 21. The dose knob/button 24 allows a user to set the dosage of medication to be injected. The outer sleeve 13 is gripped by the user when injecting medication. The cap 21 is employed by the user to securely hold the pen injector 50 in a shirt pocket, purse, or other suitable location.
FIG. 2 is an exploded view of the exemplary drug delivery pen 50 shown in FIG. 1. The dose knob/button 24 has a dual purpose and is used to both set the dosage of the medication to be injected and to inject the dosed medicament via a lead screw 7 and stopper 15 from a medicament cartridge 12, which is attached to the drug delivery pen through a lower housing 17. The medicament cartridge 12 is typically a glass tube sealed at one end with a septum 16 and at the other end with the stopper 15. In standard drug delivery pens, the dosing and delivery mechanisms are all found within the outer sleeve 13. Those mechanisms are not described in greater detail herein as they are understood by those knowledgeable of the art.
A pen needle assembly 10 includes a hub 20, a patient needle 11 extending from a patient end of the pen needle assembly, and a septum-penetrating needle cannula 18 disposed within the hub 20 on a non-patient side thereof. The septum-penetrating needle cannula 18 is in fluid communication with the patient needle 11. The hub 20 is preferably screwed onto the lower housing 17, although other attachment means can be used such as attaching directly to the medicament cartridge 12. In attaching the hub 20 to the lower housing 17 or medicament cartridge 12, the septum-penetrating cannula 18 pierces the septum 16, but the septum 16 does not move with respect to the medicament cartridge 12. The stopper 15, however, is axially displaceable within the medicament cartridge 12 while maintaining a fluid-tight seal. The distal movement of the plunger or stopper 15 within the medicament cartridge 12 (due to advancement of the lead screw 7) causes medication to be forced into the patient needle 11 of the hub 20.
To protect a user, or anyone who handles the pen injector 50, an outer shield 29, which attaches to the hub 20, covers the hub 20. The outer shield 29 can also be used as a handle or grip to screw hub 20 onto or off of pen injector 50. An inner shield 28 covers the patient needle 11 within the outer shield 29. The inner shield 28 can be secured to the hub 20 to cover the patient needle 11 by any suitable means, such as an interference fit or a snap fit. As shown in FIG. 2, the hub 20 also includes ribs 64 for engaging the outer shield 29. The outer shield 29 and inner shield 28 are removed prior to use. The cap 21 fits snugly against outer sleeve 13 to allow a user to securely carry the pen injection device 50.
To use the pen needle assembly 10, the user removes a sterile cover on the outer shield 29, twists the pen needle assembly 10 onto the pen injector 50, removes the outer shield 29, and then finally removes the inner shield 28. While there are some needle storage devices that aid in placing the pen needle assembly 10 on the pen injector 50, the user still must remove needle hub packaging, including the inner and outer shields 28 and 29, to place a needle hub onto a pen injector and ready the device for injection. This process must be repeated for each successive injection.
Pen needle assemblies are usually sold individually packaged inside a plastic cover (such as outer shield 29) with a label covering the opening in the cover to provide a sterility barrier. A need exists for a needle dispensing and storing apparatus that stores a plurality of needles before and after their use.